Short answer: A color blindness simulator shows your page the way people with color vision deficiency might see it. Chrome has one built in: open DevTools, go to the Rendering tab and pick protanopia, deuteranopia, tritanopia or achromatopsia. Then check that nothing on the page depends on color alone, starting with links and form errors.
Who sees color differently
The National Eye Institute says about 1 in 12 men have color vision deficiency, and men have a much higher risk than women. The most common type makes it hard to tell red from green.
Most people with it are born with it. The W3C adds that people with partial sight often have limited color vision, and many older users don’t see color well.
How to simulate color blindness in Chrome
| Simulation | What it shows | What to look for |
|---|---|---|
| Protanopia | No red: low perception of red; greens, reds and yellows get confused | Red error states and green success states |
| Deuteranopia | No green: low perception of green; greens, reds and yellows get confused | Charts and labels that use red against green |
| Tritanopia | No blue: low perception of blue; greens and blues get confused | Blue links and buttons next to green |
| Achromatopsia | No color: partial or total absence of color vision | Anything you can only tell apart by color |
The simulations and what they show come from Chrome for Developers, read November 5, 2026.
Chrome’s list also includes blurred vision and reduced contrast. Our color contrast checker guide covers how to measure contrast itself.
What WCAG asks
Criterion 1.4.1, at Level A, says color must not be the only visual means of conveying information, indicating an action, prompting a response or distinguishing a visual element.
The W3C notes a detail about links. A link styled exactly like the text around it doesn’t fail this criterion, because no color sets it apart, but nobody can see it’s a link either. An underline fixes that.
Where color alone causes trouble
Links that differ from the text only by color are the most common case. Form errors shown only as a red border are another; our form validation guide covers putting them in text.
Charts that use red and green for opposite results, status dots and required fields marked only in color fail the same way. By the same rule, don’t rely on color alone for states such as keyboard focus; our focus indicator guide covers them.
How to check your site for color blind visitors
- Open your page in Chrome, then DevTools, and go to the Rendering tab.
- Under Emulate vision deficiencies, pick protanopia and look at the whole page.
- Repeat with deuteranopia, tritanopia and achromatopsia.
- Check that links inside text are underlined, not only colored.
- Check that errors, warnings and success messages have words or icons.
- Check that charts and status labels have text, patterns or shapes as well as color.
- Test the light and dark themes if your site has both.
What we found on our own site
On November 5, 2026, we checked whether our pages carry anything by color alone. On two guides and the contact page, in English and Spanish, every link inside a paragraph was underlined, in the light and dark themes and at computer and phone widths. The only links without an underline were the chapter lists, which work as a menu.
One link was easy to miss: the email address on our contact page had the same color as the text around it and no underline, so nothing showed it was a link. We underlined it that night. We also looked at a guide, our home and the contact page through Chrome’s four color simulations.
Before you publish
- Links inside paragraphs are underlined.
- Error and success messages are written out.
- Required fields are marked with text or a symbol, not only color.
- Charts carry labels or patterns, not only colors.
- The page still makes sense in Chrome’s achromatopsia simulation.
- The checks hold in both themes.
RememberColor can add meaning, but it can’t carry it alone. Every color cue needs a word, a shape or an underline next to it.
Sites that work for every visitor are part of our web design service.
Quick answers about color blindness and your website
What is a color blindness simulator?
A tool that shows a page or image the way people with a color vision deficiency might see it. Chrome DevTools has one built in, in the Rendering tab, with options such as protanopia, deuteranopia, tritanopia and achromatopsia.
How common is color blindness?
The National Eye Institute says about 1 in 12 men have color vision deficiency, and that men have a much higher risk than women. The most common type makes it hard to tell red from green.
What does WCAG say about color?
Success criterion 1.4.1, at Level A, says color must not be the only visual means of conveying information, indicating an action, prompting a response or distinguishing a visual element. Add text, an icon or a pattern.
Should links be underlined for color blind users?
Underlining links inside text is the simplest way to avoid relying on color alone. If links differ from the text only by color, people who don’t see that difference can’t tell which words are links.
How do I make a color blind friendly palette?
Don’t let meaning depend on telling red from green, the most common confusion. Pair every color with a label, an icon or a pattern, and check the result in Chrome’s simulations.
Sources
Read on November 5, 2026. National Eye Institute: Color Blindness and Types of Color Vision Deficiency. W3C Web Accessibility Initiative: Understanding SC 1.4.1 Use of Color (Level A). Chrome for Developers: Apply other effects: enable automatic dark theme, emulate focus, and more. Our case: our own pages, read in a browser on November 5, 2026.